JP2007265756A - Light-emitting device, its manufacturing method, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain both improvement of an aperture ratio and restraint of voltage fall in a cathode. <P>SOLUTION: A plurality of light-emitting elements E are aligned at an element array part A over an X-direction and a Y-direction. Each light-emitting element E contains a first electrode 21, a second electrode 22, and a light-emitting layer 23 intercalated between the both electrodes. An auxiliary wiring 27, formed of a material with a resistivity lower than that of the second electrode 22, is electrically connected with the second electrode 22 of each light-emitting element E. A gap S1 between an i-th line and an (i+1)th line is wider than that S2 between the (i+1)th line and an (i+2)th line. The auxiliary wiring 27 exists in extension in an X-direction within the gap S1. No auxiliary wirings 27 are formed in the gap S2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a structure of a light emitting device using a light emitting element such as an organic light emitting diode element.

Conventionally, a light-emitting device in which a large number of light-emitting elements are arranged in a matrix has been proposed. Each light emitting element includes a first electrode, a second electrode, and a light emitting layer interposed between the two electrodes. Patent Document 1 discloses a configuration in which an auxiliary wiring is formed in a gap between light emitting elements in a top emission type light emitting device in which a light transmissive conductive film continuous over a plurality of light emitting elements is used as a second electrode. Yes. The auxiliary wiring is formed of a conductive material having a lower resistivity than the second electrode. According to this configuration, even when the second electrode is formed of a high-resistance material, the voltage drop in the second electrode is reduced, so that the voltage applied to each light emitting element is made uniform and each voltage is reduced. Gradation unevenness is suppressed.
JP 2002-352963 A

Most of the low resistance metals used as the material for the auxiliary wiring have a light shielding property. Therefore,
In the configuration in which the auxiliary wiring is arranged on the light emission side (light extraction side) when viewed from the light emitting element, the ratio of the area where the emitted light from each light emitting element is actually emitted in the region where the plurality of light emitting elements are arranged (
(Hereinafter referred to as “aperture ratio”) is limited by the auxiliary wiring. If the line width of the auxiliary wiring is reduced, it is possible to maintain a high aperture ratio. In this case, however, the increase in the resistance value of the auxiliary wiring may cause insufficient suppression of the voltage drop of the second electrode. is there.

In addition, even if an error occurs in the position of the auxiliary wiring, a space (hereinafter referred to as “margin area”) is provided between the design area where the auxiliary wiring is formed and each light emitting element so that the auxiliary wiring and the light emitting element do not overlap. May be secured). Since neither the auxiliary wiring nor the light emitting element is formed in the margin region, it is more difficult to achieve both improvement in aperture ratio and sufficient suppression of voltage drop. In view of the above circumstances, an object of the present invention is to solve the problem of achieving both improvement in aperture ratio and suppression of voltage drop in the second electrode.

In order to solve the above problems, a light-emitting device according to the present invention includes a plurality of light-emitting elements having a light-emitting layer interposed between a first electrode and a second electrode in a first direction (for example, the X direction in FIG. 2). A plurality of arrayed element groups (for example, a set of light-emitting elements belonging to each row) are formed by an element array portion arranged in parallel in a second direction intersecting the first direction, and a material having a resistivity lower than that of the second electrode. Second of light emitting element
An auxiliary wiring electrically connected to the electrode, and the auxiliary wiring includes a first element group (for example, the i-th row in FIG. 2) and a second element group ( For example, a third element that extends in the first direction with a gap from the (i + 1) th row in FIG. 2 and is adjacent to the second element group on the opposite side of the first element group. It is not formed in the gap between the group (for example, the (i + 2) th row in FIG. 2) and the second element group.

In the present invention, since no auxiliary wiring is formed in the gap between the second element group and the third element group, the auxiliary wiring is formed in the gap between all the element groups in the element array section. The area of the element array portion where the auxiliary wiring is formed and the area of the margin region can be reduced. Therefore, it becomes easy to improve both the aperture ratio and the resistance of the auxiliary wiring. For example, the aperture ratio can be improved while maintaining the line width of the auxiliary wiring, or the line width of the auxiliary wiring can be increased (low resistance) while maintaining the aperture ratio.

In a preferred embodiment of the present invention, the distance between each light emitting element of the first element group and each light emitting element of the second element group (for example, the gap S1 having a width B1 in FIG. 2) The distance between the light emitting element and each light emitting element in the third element group (for example, the gap S2 having the width B2 in FIG. 2) is wider. According to this aspect, it is possible to maintain the aperture ratio at a high level while reducing the resistance of the auxiliary wiring as compared with the configuration in which the element groups are arranged at equal intervals.

In another aspect, the second electrode is formed continuously over the plurality of light emitting elements, and the auxiliary wiring is formed immediately below or immediately above the second electrode (that is, without an insulating layer interposed between the second electrode). And is in surface contact with the second electrode. According to this configuration, the second electrode and the auxiliary wiring can be reliably conducted as compared to the configuration in which the second electrode and the auxiliary wiring are conducted through the contact hole of the insulating layer therebetween. Further, since a contact hole for conducting the second electrode and the auxiliary wiring is not required, the manufacturing process of the light emitting device can be simplified and the manufacturing cost can be reduced.
For example, the light emitting layer includes a partition layer formed on the surface of the substrate on which the first electrode of each light emitting element is disposed and having an opening corresponding to the first electrode, and the light emitting layer has a portion located inside the opening. Including, second
The electrode includes a portion facing the first electrode across the light emitting layer inside the opening and a portion covering the surface of the partition layer, and the auxiliary wiring is interposed between the partition layer and the second electrode. . According to the above configuration, since the auxiliary wiring is covered with the second electrode, it is possible to prevent corrosion of the auxiliary wiring due to adhesion of outside air or moisture.

In a preferred aspect of the present invention, each light emitting element is formed in an elongated shape along the first direction.
In other words, the auxiliary wiring extends along the longitudinal direction of each light emitting element. According to this aspect,
Compared to the configuration in which the auxiliary wiring extends along the short direction of each light emitting element, the current path width from each light emitting element to the auxiliary wiring (for example, the width W in FIG. 5) is easily ensured. The resistance value in the section from the light emitting element to the auxiliary wiring can be reduced. A specific example of this aspect will be described later as a second embodiment.

In a specific aspect of the present invention, a plurality of driving transistors for controlling the current supplied to each light emitting element and an insulating layer covering the plurality of driving transistors (for example, the second insulating layer F in FIG. 3).
2), the plurality of light emitting elements are disposed on the surface of the insulating layer, and the first electrode of each light emitting element is electrically connected to the driving transistor through a contact hole formed in the insulating layer. The
In this aspect, the contact hole corresponding to each light emitting element belonging to each of the first element group and the second element group is formed on the auxiliary wiring side as viewed from each light emitting element of the element group, more specifically, the element group. Is formed in a gap (for example, margin region M in FIG. 2) between the peripheral edge on the auxiliary wiring side of each light emitting element and the peripheral edge on the light emitting element side in the auxiliary wiring. In this embodiment, since the contact hole is formed in the side region of the auxiliary wiring where no light emitting element is present, the first electrode and the driving transistor are well connected by expanding the contact hole without reducing the aperture ratio. Is possible.
In a further preferred aspect, the contact hole is formed in an elongated shape along the first direction. According to this aspect, since a sufficient area is secured for the contact hole, it is possible to reduce the resistance of the connection portion between the first electrode and the drive transistor and to suppress poor conduction between them.

From another viewpoint, the light emitting device according to the present invention is characterized in that a plurality of element groups in which a plurality of light emitting elements having a light emitting layer interposed between a first electrode and a second electrode are arranged in a first direction are first. An element array unit arranged in parallel in a second direction intersecting the direction, and a plurality of auxiliary wirings formed of a material having a lower resistivity than the second electrode and electrically connected to the second electrode of each light emitting element Auxiliary wiring is provided for each unit (for example, a set of an even-numbered row in FIG. 2 and an odd-numbered row adjacent to the positive side in the Y direction) in which the element array section is divided into two or more element groups adjacent to each other. Extending in the first direction with a gap,
There is a configuration in which it is not formed in the gap between each element group belonging to each unit. That is, since one auxiliary wiring is formed in units of a plurality of element groups, it is easy to improve both the aperture ratio and the resistance of the auxiliary wiring.

The light emitting device according to the present invention is used in various electronic devices. A typical example of this electronic device is a device that uses a light emitting device as a display device. Examples of this type of electronic device include a personal computer and a mobile phone. However, the use of the light emitting device according to the present invention is not limited to image display. For example, an exposure device (exposure head) for forming a latent image on an image carrier such as a photosensitive drum by irradiation of light, a device (backlight) that is arranged on the back side of the liquid crystal device and illuminates it, or The light emitting device of the present invention can be applied to various uses such as various illumination devices such as a device that illuminates a document by being mounted on an image reading device such as a scanner.

The present invention is also specified as a method of manufacturing the light emitting device according to each of the above aspects. In the manufacturing method, a plurality of element groups in which a plurality of light emitting elements having a light emitting layer interposed between a first electrode and a second electrode are arranged in a first direction are arranged in parallel in a second direction intersecting the first direction. A method for manufacturing a light emitting device comprising an element array section and an auxiliary wiring electrically connected to a second electrode of each light emitting element, wherein the first element groups adjacent to each other among a plurality of element groups A region facing the gap between the first element group and the second element group (for example, an area RA in FIG. 4) is opened, and a third element group adjacent to the second element group on the side opposite to the first element group Region facing the gap between the first element group and the second element group (for example, region RB in FIG. 4)
3) including a process of preparing a mask for shielding, and a process of forming auxiliary wiring by depositing a material having a lower resistivity than the second electrode through the mask.

In the mask used in the above method, the area facing the gap between the second element group and the third element group is shielded, so that the area facing the gap between all the element groups is opened. Compared with high mechanical strength. Therefore, it is possible to suppress the error of the auxiliary wiring and the damage of the mask due to the deformation (deflection) of the mask.

<A: First Embodiment>
<Configuration of light emitting device>
FIG. 1 is a circuit diagram showing an electrical configuration of a light emitting device according to the present invention. The light emitting device includes an element array portion A in which a plurality of unit circuits (pixel circuits) U are arranged. In the element array portion A, a plurality of scanning lines 12 extending in the X direction and a plurality of data lines 14 extending in the Y direction orthogonal to the X direction are formed. Each unit circuit U is arranged at a position corresponding to each intersection of the scanning line 12 and the data line 14. Accordingly, the plurality of unit circuits U are arranged in a matrix over the X direction and the Y direction.

One unit circuit U includes a power line 16 (power voltage VEL) to a ground line 18 (ground voltage Gnd).
Drive transistor Tdr and light emitting element E arranged on the path to The light emitting element E is
Organic EL (Electro Luminescence) between the first electrode 21 and the second electrode 22 facing each other
It is an organic light emitting diode element with a light emitting layer 23 of material interposed. The light emitting element E includes the light emitting layer 2
3 emits light with a luminance corresponding to current Iel (hereinafter referred to as “drive current”) Iel. The first electrodes (anodes) 21 are formed so as to be separated from each other for each light emitting element E. The second electrode (cathode) 22 is formed continuously over the plurality of light emitting elements E and is electrically connected to the ground line 18. However, ground potential Gnd
The negative electrode voltage may be supplied to the second electrode 22 with reference to the above.

The drive transistor Tdr is a p-channel transistor that controls the amount of drive current Iel according to the gate voltage. The drain of the drive transistor Tdr is connected to the first electrode 21 of the light emitting element E. The source of the drive transistor Tdr in each unit circuit U is the power supply line 16
Are connected in common. A capacitive element C is interposed between the gate and source (power supply line 16) of the drive transistor Tdr. A selection transistor Tsl for controlling the electrical connection between the gate of the driving transistor Tdr and the data line 14 is interposed.

In the above configuration, the selection transistor T according to the scanning signal G supplied to the scanning line 12.
When sl changes to the on state, the data voltage S corresponding to the gradation designated for the light emitting element E is supplied from the data line 14 to the gate of the driving transistor Tdr via the selection transistor Tsl. At this time, the electric charge corresponding to the data voltage S is accumulated in the capacitive element C, so that the gate of the drive transistor Tdr is maintained at the data voltage S even when the selection transistor Tsl is turned off. Therefore, the drive current Iel corresponding to the data voltage S is continuously supplied to the light emitting element E.

Next, a specific configuration of the element array portion A will be described with reference to FIGS. FIG.
It is a top view which shows the structure of the element array part A, FIG. 3 is sectional drawing seen from the III-III line | wire in FIG. In FIGS. 2 and 3, the elements such as the scanning line 12, the data line 14, and the selection transistor Tsl are appropriately omitted. In each drawing referred to below, for the convenience of explanation, the ratio of dimensions of each element is appropriately changed from an actual apparatus.

As shown in FIG. 3, each element in FIG. 1 such as the drive transistor Tdr and the light emitting element E is a substrate 1.
It is formed on the 0 plane. The substrate 10 is a plate material made of various insulating materials such as glass and plastic. In addition, since the light-emitting device of this embodiment is a top emission type in which the radiated light from the light-emitting element E is emitted to the side opposite to the substrate 10, the substrate 10 is not required to have light transmittance.

A drive transistor Tdr is disposed on the surface of the substrate 10. The drive transistor Tdr includes a semiconductor layer 31 formed of a semiconductor material on the surface of the substrate 10 and a gate electrode 32 facing the semiconductor layer 31 (channel region) with the gate insulating layer F0 interposed therebetween. The gate electrode 32 is covered with the first insulating layer F1. The source electrode 33 and the drain electrode 35 of the driving transistor Tdr are formed on the surface of the first insulating layer F1 and are electrically connected to the semiconductor layer 31 (source region / drain region) through the contact hole of the first insulating layer F1. . The surface of the substrate 10 on which the driving transistor Tdr is formed is covered with the second insulating layer F2. 1st insulating layer F1 and 2nd insulating layer F2
Is a film body formed of an insulating material such as SiO ₂ .

As shown in FIGS. 2 and 3, the first electrodes 21 are formed on the surface of the second insulating layer F2 so as to be separated from each other for each light emitting element E. The first electrode 21 is a rectangular electrode whose longitudinal direction is the Y direction, and is formed of a light reflective conductive material having a work function higher than that of the second electrode 22. FIG.
As shown in FIG. 3, the first electrode 21 is electrically connected to the drain electrode 35 of the driving transistor Tdr through a contact hole CH that penetrates the second insulating layer F2 in the thickness direction.

A partition layer 25 is formed on the surface of the second insulating layer F2 on which the first electrode 21 is formed. As shown in FIGS. 2 and 3, the partition wall layer 25 has an opening 251 in each region overlapping the first electrode 21.
This is an insulating film body in which (a hole penetrating the partition wall layer 25 in the thickness direction) is formed. As shown in FIG. 2, when viewed from the Z direction, the inner peripheral edge of the opening 251 is located inside the peripheral edge (contour line) of the first electrode 21 over the entire periphery. That is, the first electrode 21 is exposed from the partition wall layer 25 through the opening 251. As described above, the periphery of the first electrode 21 is actually covered with the partition wall layer 25, but in FIG. 2, the outer shape of the first electrode 21 is shown by a solid line for convenience.

The light emitting layer 23 is continuously formed over the plurality of light emitting elements E so as to cover the entire region of the second insulating layer F2 on which the partition layer 25 is formed. That is, the light emitting layer 23 enters the inside of the opening 251 and comes into contact with the first electrode 21 (that is, the part that actually emits light) and the partition layer 25.
And a portion located on the surface. Since the first electrode 21 is formed so as to be separated from each other for each light emitting element E, the light emitting layer 23 is continuous even though the light emitting layer 23 is continuous over the plurality of light emitting elements E.
Is controlled individually for each light emitting element E according to the voltage of each first electrode 21. Various functional layers (a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, a hole block layer, and an electron block layer) for promoting or improving the light emission by the light emitting layer 23 are the light emitting layers. It is good also as a structure laminated | stacked on 23. FIG.

As shown in FIG. 3, the second electrode 22 is an electrode that is formed continuously over the plurality of light emitting elements E and covers the light emitting layer 23 and the partition layer 25. That is, the second electrode 22 includes a portion facing the first electrode 21 with the light emitting layer 23 sandwiched inside the opening 251 and a portion located on the surface of the partition layer 25. As shown in FIGS. 2 and 3, the first electrode 21, the second electrode 22, and the light emitting layer 23.
The portion located inside the inner periphery of the opening 251 in the Z direction (that is, the region where the drive current Iel flows from the first electrode 21 to the second electrode 22) is the light emitting element E. A region of the light emitting layer 23 that overlaps with the partition layer 25 does not emit light because current is blocked by the partition layer 25 interposed between the first electrode 21 and the second electrode 22. That is, the partition layer 25 functions as a means for demarcating the outline of each light emitting element E.

The second electrode 22 is formed of a light transmissive conductive material such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). Therefore, the light emitted from the light emitting layer 23 to the opposite side of the substrate 10 and the light emitted from the light emitting layer 23 toward the substrate 10 and reflected by the surface of the first electrode 21 are transmitted through the second electrode 22 and emitted. . That is, the light emitting device of this embodiment is a top emission type.

By the way, since many of the light-transmitting conductive materials have high resistivity, the second electrode 22 formed of this kind of material has a high resistance, and the voltage drop in the surface becomes remarkable. Therefore, the voltage applied to each light emitting element E differs depending on the position in the plane of the second electrode 22 (in the XY plane), and as a result, the luminance of each light emitting element E may be uneven. is there. In order to suppress such a variation in the amount of light, in the present embodiment, an auxiliary wiring 27 for assisting the conductivity of the second electrode 22 is formed. The auxiliary wiring 27 is formed of a conductive material (for example, aluminum) having a lower resistivity than the second electrode 22 and is electrically connected to the second electrode 22. The auxiliary wiring 27 of the present embodiment is formed between the second electrode 22 and the partition wall layer 25 (directly below the second electrode 22).

Next, a specific layout of each element will be described in detail with reference to FIGS.
FIG. 2 shows three columns of light-emitting elements E belonging to each row from the i-th row to the (i + 3) -th row. The i-th row and the (i + 2) -th row are even rows, and the (i + 1) -th row and the (i + 3) -th row are odd rows.

As shown in FIG. 2, the gap S1 (width B1) between each light-emitting element E in the even-numbered row and each light-emitting element E in the odd-numbered row adjacent to the positive side in the Y direction is equal to each light-emitting element E in the odd-numbered row. It is wider (B1> B2) than the gap S2 (width B2) between the light emitting elements E in even rows adjacent to the positive side in the Y direction. The auxiliary wiring 27 is formed so as to extend in the X direction within the gap S1, and is not formed in the gap S2. For example, i
An auxiliary wiring 27 is formed in each of the gap S1 between the row and the (i + 1) th row and the gap S1 between the (i + 2) th row and the (i + 3) th row, and the (i + 1) th row. The auxiliary wiring 27 does not exist in the gap S2 between the row and the (i + 2) th row. That is, the element array unit A is composed of an odd row and an even row adjacent to the positive side in the Y direction as a unit.
, The auxiliary wiring 27 is formed in the gap between the units adjacent in the Y direction, and the auxiliary wiring 27 does not exist in the gap between the rows belonging to one unit. As described above, in the present embodiment, the auxiliary wiring 27 is formed at a rate of one for each of a plurality of rows (two rows).

An error may occur at the position where the auxiliary wiring 27 is formed for reasons of manufacturing technology.
For example, when the auxiliary wiring 27 is formed by vapor deposition through a mask (details will be described later), the auxiliary wiring 2 is caused by an error in the dimension of the mask or an alignment error between the substrate 10 and the mask.
7 may be formed at a position different from the intended position (designed position). Auxiliary wiring 2
In this embodiment, the auxiliary wiring 27 and the light emitting element E are not overlapped when viewed from the Z direction even in the case where there is an error in the position 7, in the present embodiment, the design position of the auxiliary wiring 27 and its width direction (Y direction). Margin regions M are secured in the gaps between the light emitting elements E adjacent to both sides. 2 and 3
2, the margin region M is a region sandwiched between the peripheral edge on the light emitting element E side of the auxiliary wiring 27 and the peripheral edge of the light emitting element E on the auxiliary wiring 27 side (inner peripheral edge of the opening 251). .

Since the auxiliary wiring 27 is formed at a rate of one for every two rows, the margin region M is secured only in the gap S1 between the even-numbered row and the odd-numbered row on the positive side in the Y-direction, and the odd-numbered row and the Y-direction in the Y-direction. It does not exist in the gap S2 with the even-numbered row on the positive side. As shown in FIGS. 2 and 3, the contact hole CH for conducting the first electrode 21 of each light emitting element E and the driving transistor Tdr is a margin region between the light emitting element E and the auxiliary wiring 27 adjacent thereto. In M, the auxiliary wiring 27 is formed in a long shape along the X direction in which it extends. Therefore, the arrangement of the light emitting elements E and the corresponding contact holes CH in the Y direction is opposite between the odd rows and the even rows. That is, the contact hole CH is located on the positive side in the Y direction when viewed from the light emitting element E in the even-numbered rows, whereas the contact hole CH is located on the negative side in the Y direction when viewed from the light emitting elements E in the odd rows. In other words, the layout of the light emitting elements E in the odd and even rows adjacent to each other is line-symmetric with respect to the axis T extending in the X direction between the two rows.

As described above, in the present embodiment, one auxiliary wiring 27 is formed for every two rows, so that the configuration in which the auxiliary wiring 27 is formed in the gaps of all the rows (hereinafter referred to as “conventional configuration”) and In comparison, the total area required for forming the auxiliary wiring 27 and securing the margin region M in the region where the light emitting element E is distributed (element array portion A) is reduced (simply reduced in half). Therefore, there is an advantage that it is easy to maintain the aperture ratio and reduce the resistance of the auxiliary wiring 27. For example, if the aperture ratio of the element array portion A is maintained to be the same as that of the conventional configuration, the line width of each auxiliary wiring 27 is reduced by the amount of the auxiliary wiring 27 and the area of the margin region M corresponding to each. It can be secured wider than the conventional configuration. Alternatively, if the line width of each auxiliary wiring 27 is maintained to be the same as that of the conventional configuration, the auxiliary wiring 27 and the margin area M occupying the entire element array portion A.
Therefore, the area of each light emitting element E can be secured wider and the aperture ratio can be increased as compared with the conventional configuration. If the current amount of the drive current Iel is equivalent to that of the conventional configuration, the light amount of each light emitting element E can be increased by increasing the aperture ratio. In addition, since the electrical energy (drive current Iel) to be supplied to each light emitting element E in order to emit a desired amount of light from the light emitting device is reduced by increasing the aperture ratio, deterioration due to the supply of electrical energy is suppressed. Thus, there is an advantage that the life of the light emitting element E is extended.

A gap S2 (width B2) between the odd-numbered row and the even-numbered row on the positive side in the Y direction is a region that does not contribute to light emission (so-called dead space). Therefore, if the light emitting elements E in all rows are arranged at equal intervals B1 along the Y direction, there is a problem that the aperture ratio in the element array portion A is restricted. In the present embodiment, the gap S2 is narrower than the gap S1 (B2 <B1). Therefore, an increase in the aperture ratio can be easily realized as compared with the configuration in which the light emitting elements E are arranged at equal intervals B1 along the Y direction.

Incidentally, a recess reflecting the shape of the contact hole CH appears in a portion of the surface of the first electrode 21 overlapping the contact hole CH. Therefore, contact hole CH
In the configuration in which the light-emitting element E is formed so as to overlap with (that is, the configuration in which the contact hole CH exists inside the opening 251), the region of the light-emitting layer 23 is divided into a region facing the contact hole CH and the other regions. The thickness is different, which may impair the luminance uniformity of each light emitting element E. In addition, scattering of the emitted light from the light emitting element E in the depression on the surface of the first electrode 21 also causes unevenness in luminance. On the other hand, in this embodiment, Z
The light emitting element E is formed so as not to overlap with the contact hole CH when viewed from the direction.
That is, since the light emitting layer 23 of the light emitting element E is formed only on the flat surface of the first electrode 21 having no depression, the luminance of each light emitting element E can be made uniform.

Further, in the configuration in which the contact hole CH is formed outside the margin region M, there is a problem that as the area of the contact hole CH is increased, the area of the light emitting element E is reduced and the aperture ratio is reduced. On the other hand, in the present embodiment, it does not inherently contribute to light emission (
That is, since the contact hole CH is formed in the margin region M (where the light emitting element E is not formed), it is possible to sufficiently secure the area of the contact hole CH without reducing the area of the light emitting element E. For example, as shown in FIG. 2, the contact hole CH is formed in an elongated shape in the X direction, thereby reducing the contact resistance between the first electrode 21 and the drive transistor Tdr and suppressing the conduction failure between the two. is there.

<Method for manufacturing light emitting device>
Next, the process of forming the auxiliary wiring 27 in the method for manufacturing the light emitting device according to the present embodiment will be described. The auxiliary wiring 27 of this embodiment is formed by vapor deposition (vacuum vapor deposition) using a mask. It should be noted that all known techniques are employed for forming elements other than the auxiliary wiring 27.

FIG. 4 is a cross-sectional view for explaining a process of forming the auxiliary wiring 27 (cross section corresponding to FIG. 3).
It is. As shown in FIG. 4, a vapor deposition mask 50 is prepared prior to the formation of the auxiliary wiring 27. The mask 50 is formed in a shape that opens the region RA and shields the other region RB. The region RA is a slit-like region extending along the X direction so as to face the region where the auxiliary wiring 27 is formed. That is, the region RA is an even-numbered row (i-th row or (i + 2) th row).
Line) and an odd-numbered line (the (i + 1) th line or the (i + 3) th line) adjacent to the positive side in the Y-direction (more specifically, a region excluding the margin region M from the gap S1) ). On the other hand, the region RB includes a region RB1, a region RB2, and a region RB3. The region RB1 is a region facing each light emitting element E. The region RB2 is a region facing the margin region M. Region RB3 is
This is an area having a width B2 facing the gap S2 between the odd-numbered row ((i + 1) th row) and the even-numbered row ((i + 2) th row) on the positive side in the Y direction.

The auxiliary wiring 27 is formed by vapor deposition using the mask 50 described above. That is, the light emitting device in the stage where the light emitting layer 23 is formed (before the formation of the second electrode 22) is placed in a vacuum,
A mask 50 is disposed so as to face the light emitting layer 23. Then, a vapor V of a conductive material having a resistivity lower than that of the second electrode 22 is blown from the mask 50 side to the light emitting device. In the above process, the vapor V blocked by the region RB of the mask 50 does not reach the light emitting device, and the mask 50
The vapor V that has passed through the region RA is selectively attached and deposited on the surface of the light emitting layer 23, whereby the auxiliary wiring 27 is formed in the shape of FIG.

In the light emitting device of the present embodiment, since one auxiliary wiring 27 is formed for every two rows of the light emitting elements E, it is not necessary to open the region RB3 of the mask 50 as shown in FIG. That is, the mechanical strength of the mask 50 is sufficiently higher than when the auxiliary wiring 27 is formed in the gaps of all rows as in the conventional configuration (when the region RB3 is opened in addition to the region RA of the mask 50). Can be maintained. Therefore, it is possible to suppress an error in the size and position of the auxiliary wiring 27 caused by deformation of the mask 50 (for example, bending due to its own weight).

<B: Second Embodiment>
Next, a second embodiment of the present invention will be described. In the present embodiment, elements common to the first embodiment are denoted by the same reference numerals as those described above, and detailed description thereof is omitted as appropriate.

FIG. 5 is a plan view (a plan view corresponding to FIG. 2) showing the configuration of the element array portion A according to the present embodiment. In 1st Embodiment, the structure which the auxiliary wiring 27 extended along the short side (X direction) of the light emitting element E was illustrated. On the other hand, the auxiliary wiring 27 in the present embodiment extends along the long side (Y direction) of the light emitting element E as shown in FIG. In FIG. 5, three rows of light emitting elements E belonging to each column from the jth column to the (j + 3) th column are shown. The jth column and the (j + 2) th column are even columns, and the (j + 1) th column and the (j + 3) th column are odd columns.

As shown in FIG. 5, in this embodiment, one auxiliary wiring 27 is formed for each of a plurality of columns (two columns). That is, the gap S1 between the j-th column and the (j + 1) -th column and the gap S1 (width B1) between the (j + 2) -th column and the (j + 3) -th column are auxiliary elements extending in the Y direction. While the wiring 27 is formed, the (j + 1) th column and the (
The auxiliary wiring 27 is not formed in the gap S2 (width B2 (<B1)) with the j + 2) column. Therefore, the same effect as the first embodiment is achieved.

Next, a resistance value (hereinafter referred to as “cathode side resistance”) in a section until the drive current Iel that has passed through each light emitting element E flows into the auxiliary wiring 27 will be examined. The cathode side resistance R is proportional to the distance L from the peripheral edge of the light emitting element E to the auxiliary wiring 27 and inversely proportional to the dimension W of the light emitting element E along the direction in which the auxiliary wiring 27 extends (see FIGS. 2 and 5). ). In the second embodiment, since the auxiliary wiring 27 extends along the long side of the light emitting element E, the dimension W is larger than that in the first embodiment in which the auxiliary wiring 27 extends along the short side of the light emitting element E. Can be secured sufficiently. Therefore, according to the present embodiment, the cathode side resistance R is reduced as compared with the first embodiment. As a result, the voltage drop at the second electrode 22 is suppressed, so that the power supply voltage VEL required for driving the light emitting element E can be reduced as compared with the case where the cathode side resistance R is high.

In the present embodiment, since the auxiliary wiring 27 extends along the long side of the light emitting element E,
The margin region M corresponding to one light emitting element E is enlarged as compared with the first embodiment, and thereby the area of the contact hole CH in the margin region M can be increased. Therefore, the first electrode 21 and the drive transistor Tdr can be made to conduct well while avoiding a decrease in the aperture ratio due to the enlargement of the contact hole CH.

<C: Third Embodiment>
Next, a third embodiment of the present invention will be described. In the present embodiment, elements common to the first embodiment are denoted by the same reference numerals as those described above, and detailed description thereof is omitted as appropriate.

6 is a plan view (plan view corresponding to FIG. 2) showing the configuration of the element array portion A according to the present embodiment, and FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. In the first embodiment, the configuration in which the auxiliary wiring 27 and the contact hole CH do not overlap is illustrated. On the other hand, in this embodiment, as shown in FIGS. 6 and 7, the contact hole C is viewed from the Z direction.
An auxiliary wiring 27 is formed so as to overlap with H. That is, the auxiliary wiring 27 is connected to the partition wall layer 2.
5, the contact hole CH of each light-emitting element E in the odd-numbered row and its Y
It overlaps with the contact holes CH of the light emitting elements E in even rows adjacent to the positive side in the direction. The configuration in which the auxiliary wiring 27 is not formed in the gap between the odd-numbered row and the even-numbered row on the positive side in the Y direction is the same as in the first embodiment. Further, a gap between the peripheral edge of the auxiliary wiring 27 and the peripheral edge of the light emitting element E (a part of the gap between the peripheral edge of the contact hole CH and the light emitting element E) is a margin region M.

According to the above configuration, since the resistance value of the auxiliary wiring 27 is reduced as compared with the first embodiment, the effect of suppressing the voltage drop in the second electrode 22 becomes more remarkable. 6 and 7 exemplify a modification of the light emitting device of the first embodiment, the auxiliary wiring 27
Is overlapped with the contact hole CH, and the same applies to the light emitting device of the second embodiment.

In addition, since the auxiliary wiring 27 has a light shielding property, even if the light emitted from the light emitting element E or external light reaches the dent in the portion of the surface of the first electrode 21 that overlaps the contact hole CH, the scattered light in this dent. Is blocked by the auxiliary wiring 27 and does not exit to the outside. Therefore, there is also an advantage that luminance uniformity is realized over the entire element array portion A.

<D: Modification>
Various modifications can be made to each of the above embodiments. An example of a specific modification is as follows. In addition, you may combine each following aspect suitably.

(1) Modification 1
In each of the above embodiments, the configuration in which the auxiliary wiring 27 is formed at the rate of one for every two rows (two columns in the second embodiment) is illustrated. However, the ratio between the number of rows or the number of columns and the auxiliary wiring 27 is illustrated. Are appropriately changed. For example, one auxiliary wiring 27 may be formed in units of three rows (three columns) or more of the light emitting elements E. Further, the pitch at which the auxiliary wirings 27 are arranged (the number of rows and columns of the light emitting elements E positioned in the gaps between the auxiliary wirings 27 adjacent to each other) does not necessarily have to be common throughout the entire element array portion A. Depending on the position in the array part A, the density of the auxiliary wirings 27 may be varied.

(2) Modification 2
In each of the above embodiments, the configuration in which the light emitting layer 23 is formed so as to be continuous over the plurality of light emitting elements E is exemplified. However, the configuration in which the light emitting layer 23 is separated for each light emitting element E (for example, the light emitting layer 23 is a partition wall). The configuration formed only inside the opening of the layer 25 is also employed. The partition layer 25 is omitted as appropriate.

(3) Modification 3
The specific configuration of the unit circuit U in each of the above embodiments is arbitrary. For example, FIG. 1 illustrates a voltage programming circuit in which the luminance of the light emitting element E is determined according to the voltage value of the data line 14, but the luminance of the light emitting element E is determined according to the current value of the data line 14. It may be a current programming circuit. In each of the above embodiments, the active matrix type light emitting device in which the driving current Iel is controlled by the driving transistor Tdr is exemplified. However, the present invention is also applied to a passive matrix type light emitting device in which the unit circuit U does not include an active element. Applied.

(4) Modification 4
In each of the above embodiments, the configuration in which the auxiliary wiring 27 is interposed between the partition wall layer 25 and the second electrode 22 is illustrated, but the position where the auxiliary wiring 27 is disposed is appropriately changed. For example, the auxiliary wiring 27 may be formed on the upper surface of the second electrode 22 (surface opposite to the partition wall layer 25). According to the configuration in which no other layer such as an insulating layer is interposed between the auxiliary wiring 27 and the second electrode 22 (that is, the configuration in which the auxiliary wiring 27 is formed immediately above or immediately below the second electrode 22), the auxiliary wiring 27 and By forming one of the second electrodes 22 following the other, both are electrically connected. Therefore, for example, compared with a configuration in which an insulating layer is interposed between them (a configuration in which the auxiliary wiring 27 and the second electrode 22 are conducted through a contact hole in the insulating layer), the manufacturing process is simplified and the manufacturing cost is reduced. Realized.

However, the auxiliary wiring 27 may be formed closer to the substrate 10 than the light emitting layer 23. For example,
An auxiliary wiring is formed by patterning the same conductive film as the gate electrode 32 of the driving transistor Tdr, and is electrically connected to the second electrode 22 through a contact hole that penetrates the first insulating layer F1 and the second insulating layer F2. A configuration is also adopted.

(5) Modification 5
In each of the above embodiments, the light emitting element E including the light emitting layer 23 made of an organic EL material has been exemplified, but the light emitting element E in the present invention is not limited to this. For example, various light emitting elements E such as a light emitting element E including a light emitting layer 23 made of an inorganic EL material and an LED (Light Emitting Diode) element.
Can be adopted. The light-emitting element E in the present invention may be an element that emits light by supplying electric energy (typically supplying current), and its specific structure and material are not limited.

<E: Application example>
Next, an electronic apparatus using the light emitting device according to the present invention will be described. 8 to 10
The figure shows the form of an electronic apparatus that employs the light-emitting device according to any one of the above forms as a display device.

FIG. 8 is a perspective view showing the configuration of a mobile personal computer employing a light emitting device. The personal computer 2000 includes a light emitting device D that displays various images, and a main body 2010 on which a power switch 2001 and a keyboard 2002 are installed. Since the light emitting device D uses an organic light emitting diode element as the light emitting element E, it is possible to display an easy-to-see screen with a wide viewing angle.

FIG. 9 is a perspective view illustrating a configuration of a mobile phone to which the light emitting device is applied. Mobile phone 300
0 includes a plurality of operation buttons 3001 and scroll buttons 3002 and a light emitting device D that displays various images. By operating the scroll button 3002, the screen displayed on the light emitting device D is scrolled.

FIG. 10 shows a personal digital assistant (PDA: Personal Digital Assistant) to which a light emitting device is applied.
It is a perspective view which shows the structure of s). The portable information terminal 4000 includes a plurality of operation buttons 4001, a power switch 4002, and a light emitting device D that displays various images. When the power switch 4002 is operated, various kinds of information such as an address book and a schedule book are displayed on the light emitting device D.

Electronic devices to which the light emitting device according to the present invention is applied include digital still cameras, televisions, video cameras, car navigation devices, in addition to the devices shown in FIGS.
Examples include pagers, electronic notebooks, electronic paper, calculators, word processors, workstations, videophones, POS terminals, printers, scanners, copiers, video players, devices equipped with touch panels, and the like. Further, the use of the light emitting device according to the present invention is not limited to the display of images. For example, in an image forming apparatus such as an optical writing type printer or an electronic copying machine,
An optical head (writing head) that exposes a photoconductor according to an image to be formed on a sheet is used. The light emitting device of the present invention is also used as this type of optical head.

It is a circuit diagram which shows the electrical constitution of the light-emitting device which concerns on 1st Embodiment of this invention. It is a top view which shows the structure of an element array part. It is sectional drawing seen from the III-III line in FIG. It is sectional drawing for demonstrating the process of forming auxiliary wiring. It is a top view which shows the structure of the element array part in 2nd Embodiment. It is a top view which shows the structure of the element array part in 3rd Embodiment. It is sectional drawing seen from the VII-VII line in FIG. It is a perspective view which shows the form (personal computer) of the electronic device which concerns on this invention. It is a perspective view which shows the form (cellular phone) of the electronic device which concerns on this invention. It is a perspective view which shows the form (mobile information terminal) of the electronic device which concerns on this invention.

Explanation of symbols

A ... element array section, 12 ... scanning line, 14 ... data line, 16 ... power line, 18 ... ground line, U ... unit circuit, E ... light emitting element, Tdr ... drive transistor, 10 ... Substrate, F
0 …… Gate insulating layer, F1 …… First insulating layer, F2 …… Second insulating layer, 21 …… First electrode, 22
2nd electrode, 23 Light emitting layer, 25 Partition wall, 27 Auxiliary wiring, M Margin area.

Claims (12)

An element array unit in which a plurality of element groups in which a plurality of light emitting elements having a light emitting layer interposed between a first electrode and a second electrode are arranged in a first direction are arranged in parallel in a second direction intersecting the first direction; ,
An auxiliary wiring formed of a material having a lower resistivity than the second electrode and electrically connected to the second electrode of each light emitting element;
The auxiliary wiring extends in the first direction by a gap between the first element group and the second element group adjacent to each other among the plurality of element groups, and the auxiliary wiring is connected to the second element group. Thus, the light emitting device is not formed in a gap between the third element group adjacent to the opposite side of the first element group and the second element group. The distance between each light emitting element of the first element group and each light emitting element of the second element group is the second
The light-emitting device according to claim 1, wherein the distance between each light-emitting element of the element group and each light-emitting element of the third element group is wider. The second electrode is continuously formed across a plurality of light emitting elements,
The light emitting device according to claim 1, wherein the auxiliary wiring is formed immediately below or immediately above the second electrode and is in surface contact with the second electrode. A partition layer formed on a surface of the substrate on which the first electrode of each light emitting element is disposed and having an opening corresponding to the first electrode;
The light emitting layer includes a portion located inside the opening,
The second electrode includes a portion facing the first electrode across the light emitting layer inside the opening, and a portion covering the surface of the partition layer,
The light emitting device according to claim 3, wherein the auxiliary wiring is interposed between the partition wall layer and the second electrode. The light emitting device according to claim 3, wherein each of the light emitting elements is formed in a long shape along the first direction. A plurality of drive transistors for controlling the current supplied to each light emitting element;
An insulating layer covering the plurality of driving transistors,
The plurality of light emitting elements are disposed on a surface of the insulating layer,
The light-emitting device according to claim 1, wherein the first electrode of each light-emitting element is electrically connected to the drive transistor through a contact hole formed in the insulating layer. The contact hole corresponding to each light emitting element belonging to each of the first element group and the second element group is formed on the auxiliary wiring side as viewed from each light emitting element of the element group. Light emitting device. The contact hole corresponding to each light emitting element belonging to each of the first element group and the second element group includes a peripheral edge on the auxiliary wiring side of each light emitting element belonging to the element group and the light emitting element in the auxiliary wiring. The light emitting device according to claim 7, wherein the light emitting device is formed in a gap with a peripheral edge on the side. The light emitting device according to claim 6, wherein the contact hole is formed in an elongated shape along the first direction. An element array unit in which a plurality of element groups in which a plurality of light emitting elements having a light emitting layer interposed between a first electrode and a second electrode are arranged in a first direction are arranged in parallel in a second direction intersecting the first direction; ,
A plurality of auxiliary wirings formed of a material having a lower resistivity than the second electrode and electrically connected to the second electrode of each light emitting element;
The auxiliary wiring extends in the first direction with a gap of each unit dividing the element array section for each of two or more element groups adjacent to each other, and in the gap of each element group belonging to each unit. A light emitting device which is not formed.   An electronic apparatus comprising the light-emitting device according to claim 1. An element array unit in which a plurality of element groups in which a plurality of light emitting elements having a light emitting layer interposed between a first electrode and a second electrode are arranged in a first direction are arranged in parallel in a second direction intersecting the first direction; A method of manufacturing a light emitting device comprising an auxiliary wiring electrically connected to the second electrode of each light emitting element,
A region facing the gap between the first element group and the second element group adjacent to each other among the plurality of element groups is opened. What is the first element group relative to the second element group? 3rd adjacent to the other side
Providing a mask for shielding a region facing the gap between the element group and the second element group;
Forming the auxiliary wiring by evaporating a material having a lower resistivity than that of the second electrode through the mask.

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